A simple text file with configuration options would be fine if and only if there was an easy way to edit that file on the device itself. Otherwise a "long" menu with all advanced configuration options would be much more suitable.

OTFM can edit text files

@szlevi Q1: there is the changelog, if the problem is not present, it is not been solved
Q2: which one? the old pdfreader? yes
the previous version of the newer one? why would you like to use it?